The RV870 Story: AMD Showing up to the Fight
by Anand Lal Shimpi on February 14, 2010 12:00 AM EST- Posted in
- GPUs
Carrell Loses His Baby: Say Goodbye to Sideport
Sitting at dinner with Eric Demers and Carrell Killebrew is honestly one of the best experiences I’ve ever had working with ATI. Before he got huge and subsequently left, I used to have annual dinners with Pat Gelsinger at Intel. They were amazing. To get to sit at the same table as someone as talented and passionate as a Gelsinger, Demers or Killebrew is one of the most fortunate and cherished parts of my job.
Eric was telling me about how they trimmed down 870 from over 400mm2 down to 334mm2 and how wonderful the end product was. I stopped him and asked for more detail here. I wanted an example of a feature that they had to throw out but they really wanted to keep in. Manufacturers rarely tell you what they threw out, marketing likes to focus on what’s in the chip and make everything sound like a well calculated move. Thankfully, marketing wasn’t allowed to speak at my dinner.
Eric turned to Carrell and said: “i know one feature we could talk about.”
“Sideport”.
Carrell responded, “OH MY GOD, that’s totally not fair.” (note that Carrell does not sound like a teenage girl, imagine that phrase just spoken more engineer-y).
When ATI first talked about the Radeon HD 4870 X2 they told us about a feature called Sideport. It was a port off each RV770 GPU that could be used for GPU-to-GPU communication.
Sideport as it was intended to be used
The whole point of doing CrossFire in alternate frame rendering mode (AFR) is that the chips never have to talk. The minute you have to start synchronizing them, you kill performance. Sideport was supposed to alleviate that.
Unfortunately, due to power reasons, Sideport was never used on the 4870 X2. ATI’s reference design had it disabled and all vendors followed suit.
Sideport was Carrell Killebrew’s favorite feature, and he had to give it up.
In early 2008 ATI realized they had to cut this chip down from 20 - 22mm on a side to 18mm, everyone had to give up something. Carrell was the big advocate for making 870 smaller, he couldn’t be a hypocrite and not give anything up.
A bunch of my conversation with Carrell at this point had to go off the record. Sideport would have been useful in RV870, but it’s unfortunately not there. Although he did tell me not to be surprised if I saw Sideport again at some point. Carrell doesn’t give up easily.
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tomoyo - Monday, February 15, 2010 - link
Another awesome article about the real situation behind the hardware from you Anand! I was on the USS Hornet and wish I had talked to you, but it was a great time nonetheless. It's interesting the change in their thought process between the RV770 and RV870, I hope they keep the winning streak up for the next refresh cycle (which hopefully will stay on the market bulges).WT - Monday, February 15, 2010 - link
*sigh* ^^^There's always one in the crowd.
Take care in the fact that you are the only person who hasn't enjoyed this read.
MegaManX4 - Monday, February 15, 2010 - link
Reminds me much of the Anglo-Saxon "documantaries", where it is always of tertiary relevance WHAT is actually discussed, but it is always of utmost interest how the responsible person "feels" about what he is just seeing, other than just stating the facts.There seems to be a huge crowd vowing for that kind of journalism, Whatever pleases the canaille.
"Jedem das Seine" or "to each his own" then
MegaManX4 - Monday, February 15, 2010 - link
This was actually the worst article i have ever read at anandtech. I know that you Americans always strive for emotionally .Driven stories, but this outright borders on silly exaggeration."Heroes of our Industry", what a Schmalz.
Also, if one would take the real informations presented in that article, it wouldn't justify even a 2 Page Article, let alone that 11 Page behemoth.
They are engineers, they do their jobs. Nothing more, nothing less.
Greetings from Germany
blowfish - Monday, February 15, 2010 - link
hmm, with an attitude like that you'll never get past middle management!Like most here, I loved this article. Anand obviously has the friendship and respect of some very senior players, and we were treated to some great insights into how things work at AMD ATI.
As the reader, you can choose to read or not read the article, simple as that. Maybe you should up your medication.
MegaManX4 - Monday, February 15, 2010 - link
unreasonable polemicpmonti80 - Monday, February 15, 2010 - link
You are the one being unreasonable. This may not be a "scientifically written" article, but no one is claiming it to be. And that's the reason this article is so interesting.saiga6360 - Thursday, February 18, 2010 - link
Apparently German engineers are just soulless robots. His confusion is understandable.BelardA - Monday, February 15, 2010 - link
I enjoyed this article even more than the RV770. I do recommend that everyone read that one too.Kind of shocking that Nvidia didn't use that info from the RV770 article to learn to NOT make big GPUs like the GTX 2xx. yeah yeah, it takes 2-4 years to design a chip.
I thank ATI (and AMD) for not playing marketing games like Nvidia does... I think they have a bigger marketing department than engineers nowadays. They started with the GF2-MX 400 & GF4-MX cards (which were re-labeled updated GF2 cards that were not up to GF3 standards)... but the latest cluster-muck of Nvidia products is nothing but a mess. 8800 re-badged as a 9800 re-badged into the gts 250. Code-name of NVxx go to G80 to G92 to G100. The GT-1xx products that are actually low-end 9xxx products, same with most G200 & G300. I'm not going to be surprised when the GTX 285 gets renamed into the GTS450 at $200! I've seen people who bought the GTS250 and post on the internet "why isn't my new gts250 much faster than my old 8800GT"... because you bought a faster version of your card and thought it was something new. Wow, 3 years with 3 names for the same product, that is marketing.
ATI does good with the entire 4000 series being DX 10.1 products and 5000s are DX11. (Does anyone really use HD-5xxx?) It doesn't feel like ATI is pulling our chain with their products.
AMD should be learning from ATI, they are getting better with CPUs - 2 years late, but AMD CPUs are now faster than Core2 and compete well against the lower end intel i-confused model CPUs. There is still room for improvement which was recommend to them some time ago, but AMD is just going to come out with a new design for next year. But had AMD tweaked their CPUs a bit for another 10~20% performance, they'd be up there with i7s.
I hope in the next ATI GPU, some form of Physics engine is added to go up against nvidia's PhsyX. But perhaps that'll be part of DX12... but Microsoft no longer supports Games for Windows.
Actually, with more and more games going ONLY to consoles, I don't think the need for high-end gaming cards will be needed anymore in the next few years. If there are no games, who needs a $300 3D Gaming card?
Zink - Monday, February 15, 2010 - link
Would also like to say great article. I can't wait for new distributed computing cores come out optimized for ATI's architectures.